What is an alternative to ceftriaxone (Ceftriaxone) for fracture prophylaxis in a patient with a penicillin (PCN) allergy?

Alternative Antibiotic for Fracture Prophylaxis in Penicillin Allergy

For patients with penicillin allergy requiring fracture surgery, clindamycin 900 mg IV or vancomycin 30 mg/kg over 120 minutes are the recommended alternatives to cefazolin. 1, 2

Primary Alternatives Based on Allergy Severity

For Most Penicillin-Allergic Patients

• Clindamycin 900 mg IV slow infusion is the first-line alternative for closed fractures requiring internal fixation in patients reporting penicillin allergy 1, 2
• Re-inject 600 mg if surgical duration exceeds 4 hours 1
• Limit administration to the operative period (maximum 24 hours) 1, 2

For Severe or Confirmed IgE-Mediated Allergy

• Vancomycin 30 mg/kg IV over 120 minutes is indicated for patients with documented severe penicillin reactions or when methicillin-resistant staphylococcus is suspected 1, 2, 3
• The infusion must be completed at least 30 minutes before incision, ideally ending right at the start of surgery 1
• Single dose is sufficient for most procedures 1

Important Consideration: Cephalosporins May Be Safe

Most patients with reported penicillin allergy can actually receive cephalosporins safely. 1, 4

• The true cross-reactivity rate between penicillin and cephalosporins is only 2-5%, not the commonly quoted 10% 1, 5
• Second and third-generation cephalosporins (like cefuroxime) have minimal cross-reactivity with penicillin 1, 6
• Cefuroxime 1.5g IV can be safely administered to most patients with penicillin allergy history, except those with severe T-cell-mediated reactions 4
• A recent study of 155 patients with penicillin allergy history who received cefuroxime showed zero allergic reactions 4

When Cephalosporins Should Be Avoided

• Documented severe IgE-mediated reactions to penicillin (anaphylaxis, angioedema) 1
• Severe T-cell-mediated reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS) 4
• First-generation cephalosporins (cefazolin, cephalexin) have higher cross-reactivity and should be avoided 1, 6

Algorithm for Antibiotic Selection

1. Obtain detailed allergy history - specifically ask about reaction type and timing 1

2. If mild/remote/unclear penicillin allergy:

   • Consider second-generation cephalosporin (cefuroxime 1.5g IV) with monitoring 4
   • This provides superior coverage compared to non-beta-lactam alternatives 4

3. If documented severe immediate reaction or patient refuses cephalosporin:

   • Use clindamycin 900 mg IV for routine cases 1, 2
   • Use vancomycin 30 mg/kg IV if MRSA risk or severe contamination 1, 2

4. For open fractures with penicillin allergy:

   • Clindamycin 900 mg IV plus gentamicin 5 mg/kg/day for enhanced gram-negative coverage 1
   • Continue for 48 hours maximum 1

Critical Timing Considerations

• Administer antibiotics within 60 minutes before surgical incision for closed fractures 2, 7
• For open fractures, start antibiotics immediately upon presentation - delaying beyond 3 hours significantly increases infection risk 2, 8, 7
• Complete vancomycin infusion before incision due to 120-minute infusion time 1

Common Pitfalls to Avoid

• Do not automatically avoid all cephalosporins - 90% of patients with penicillin allergy history can safely receive second/third-generation cephalosporins 1, 4
• Do not use vancomycin routinely - reserve for documented severe allergy or MRSA concerns, as it increases infection risk compared to cefazolin 9
• Do not extend prophylaxis beyond 24 hours for closed fractures without evidence of infection 1, 2
• Do not delay antibiotic administration while obtaining detailed allergy history in open fractures - start empiric therapy immediately 8, 7